banks cannot monitor every account everyday.
That was certainly true historically, but it is not true with all-electronic systems. Whether "the state" has the will to have the banks monitor "everything" will probably depend of the geopolitics of the moment, indefinitely into the future.
I think the underlying question is the state's assumed right to know the financial doings of all people, all the time, in all places. In my opinion, society has come to accept the notion that it is OK when the state cannot catch a crime being committed (say child porn), for them to sift through the minutia of peoples' lives looking for crumbs that might lead to post hoc evidence of the crime. My instinct is that this is a very bad development and that it leads to a huge intrusion of the state in everyone's life in exchange for a very small overall benefit to society. This is not to say stopping child porn is wrong (example only), but rather that the methods are inappropriate. To apply a
reductio, the state could stop child porn completely by seizing every child at birth and slaughtering it for its own protection. Most people would think that was "going too far." I think that watching everyone's financial transactions is also "going too far". The ends do not justify the means.
Lest you think I'm venturing too far into hypotheticals - the Canadian government recently tried to enact "watch everything on the Net" legislation, and the government line was "... either stand with us or with the child pornographers—Vic Toews, Minister of Public Safety" The government withdrew (for now) after public outcry.
http://www.cbc.ca/news/technology/story/2012/02/13/technology-lawful-access-toews-pornographers.htmlSimilar drama is starting to play out in the financial arena, and
BTC will inevitably be a political football.